:root{--bg:#0d1117;--panel:#131a22;--tile:#1f2833;--text:#e6edf3;--accent:#38bdf8}*{box-sizing:border-box}body{margin:0;background:radial-gradient(circle at top,#162238,var(--bg) 55%);color:var(--text);font-family:Avenir Next,Segoe UI,sans-serif}main{max-width:880px;margin:0 auto;padding:2rem 1rem 3rem}.card{border:1px solid #243042;background:color-mix(in srgb,var(--panel) 90%,#000 10%);border-radius:14px;padding:1rem}.board{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));grid-gap:.5rem;gap:.5rem;margin:1rem 0}.cell{min-height:60px;border-radius:10px;background:var(--tile);border:1px solid #2d3b4f;display:grid;place-items:center;font-weight:700}.controls{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));grid-gap:.5rem;gap:.5rem}button{border:1px solid #3b82f6;color:#dff4ff;background:#0f2949;border-radius:8px;padding:.5rem .75rem;cursor:pointer}button:hover{background:#113864}.meta{display:flex;gap:1rem;font-size:.95rem;color:#9fb2c9}